Wellbore: 20.06.1978 - 34/10-1 - Factpages - Norwegian Offshore Directorate

General information

General information
Attribute	Value
Wellbore name Official name of wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	34/10-1
Type Wellbore type. Legal values: EXPLORATION, DEVELOPMENT, OTHER (see 'Purpose' for more information)	EXPLORATION
Purpose Final classification of the wellbore. Legal values for exploration wellbores: WILDCAT, APPRAISAL, WILDCAT-CCS, APPRAISAL-CCS. Legal values for development wellbores: OBSERVATION, PRODUCTION, INJECTION, INJECTION-CCS, OBSERVATION-CCS. Legal values for other wellbores: SOIL DRILLING (drilling in connection with track surveys and other subsurface surveys to investigate the soil conditions prior to placement of facilities), SHALLOW GAS (drilling to investigate shallow gas before the first 'real' drilling on the location), PILOT (drilling to investigate the geology and fluid connectors for location of the main wellbore), SCIENTIFIC (drilling according to Law of Scientific research and exploration), STRATIGRAPHIC (driling according to Law of Petroleum activities §2-1).	WILDCAT
Status Status for the wellbore. Legal values are: BLOWOUT: A blowout has occurred in the well. CLOSED: A development wellbore that has been closed in a shorter or longer periode. Also applies to development wellbores where drilling is completed, but production/injection has not yet been reported. DRILLING: The well is in the drilling phase - can be active drilling, logging, testing or plugging, JUNKED: The drilling operation has been terminated due to technical problems. P&A: Exploration: The well is plugged and abandoned, and can not be reentered for further use. Development wells: The production/injection from/to the well is stopped and the well is plugged. The wellhead is removed or else made unavailable for further well operations. PLUGGED: The wellbore has been plugged, but the upper parts of the wellbore can be re-used. A sidetrack might be drilled at a later stage. PRODUCING: It was produced from the wellbore at the time of the operators last monthly report to the Norwegian Offshore Directorate. INJECTING: It was injected to the wellbore at the time of the operators last monthly report to the Norwegian Offshore Directorate. PREDRILLED: The upper part of the well has been drilled, usually as part of a batch-drilling campaign covering several wellbores. RE-CLASS TO DEV: Exploration wellbore that is reclassified to a development wellbore. RE-CLASS TO TEST: Exploration wellbore that is reclassified to test production. SUSPENDED: The drilling operation in the wellbore has been temporarily stopped. The current plan is to continue drilling later on.	P&A
Factmaps in new window	link to map
Main area Name of the area on the Norwegian Continental Shelf where the wellbore is located. Legal values: BARENTS SEA, NORWEGIAN SEA, NORTH SEA.	NORTH SEA
Field Name of the field the wellbore is related to.	GULLFAKS
Discovery Name of the discovery the wellbore is related to.	34/10-1 Gullfaks
Well name Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	34/10-1
Seismic location Position of spud location on seismic survey lines. SP: shotpoint.	LINE ST 24.5 & SP 1373
Production licence Official designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion).	050
Drilling operator Name of the licensee starting the drilling operation on behalf of the active production license (well head position). This will usually equal the operator of the production license.	Den norske stats oljeselskap a.s
Drill permit The drilling permit number together with the version of the drilling permit as stated in the drilling permit granted by the Norwegian Offshore Directorate.	197-L
Drilling facility Norwegian Offshore Directorate's name of the facility which the wellbore was drilled from.	ROSS RIG (1)
Drilling days Number of days from wellbore entry to wellbore completion.	80
Entered date The date when he wellbore was spudded. For sidetracks: The date when new formation was drilled by kicking off from the mother-wellbore,	20.06.1978
Completed date Exploration wellbores from moveable facilities: For floating facilities - date when anchor handling is started. For jackups - date the jacking-down started. Exploration wellbores from fixed facilities and all development wellbores: Date when the wellbore is at total depth, and last casing, liner or screen is set. In case of immediate plugging of the wellbore, completed date equals the date the last plug i set in the wellbore. Date when the wellbore is at total depth, and last casing, liner or screen is set. In case of immediate plugging of the wellbore, completed date equals the date the last plug i set in the wellbore.	08.09.1978
Release date Date when raw data which has been reported to the authorities from the wellbore is not confidential any longer. Normally 2 years after finishing the drilling. May be earlier if the area of the production license is relinquished.	08.09.1980
Publication date Date quality control of the wellbore information was completed, so it can be published on the internet as a 'Well Data Summary Sheet' wellbore with more information available than other wellbores.	05.12.2012
Purpose - planned Pre-drill purpose of the wellbore. Legal values for exploration wellbores: WILDCAT, APPRAISAL, WILDCAT-CCS, APPRAISAL-CCS. Example of legal values for development wellbores: OBSERVATION, PRODUCTION, INJECTION.	WILDCAT
Reentry Status whether the wellbore has been re-entered (YES) or not (NO). Re-entered wellbores are not included in the count when wellbores are presented in statistical overviews.	NO
Content For exploration wellbores, status of discovery. Legal values: DRY, SHOWS (trace amounts of hydrocarbons), GAS, GAS/CONDENSATE, OIL or OIL/GAS. SHOWS (GAS SHOWS, OIL SHOWS or OIL/GAS SHOWS) are detected as fluorescent cut (organic extract), petroleum odour, or visual stain on cuttings or cores, or as increased gas reading on the mud-loggers gas detection equipment. Legal values for WILDCAT-CCS and APPRAISAL-CCS: WATER For development wellbores, type of produced/injected fluid. Legal values: WATER, CUTTINGS, NOT AVAILABLE, OIL, GAS/CONDENSATE, OIL/GAS, CO2, GAS, WATER/GAS, NOT APPLICABLE.	OIL
Discovery wellbore Indicator which tells if the wellbore made a new discovery. Legal values: YES, NO. Prior to press-release or other information regarding drilling results, the indicator will be “NO” as a default.	YES
1st level with HC, age Age of lithostratigraphic unit, 1st level, where hydrocarbons were encountered. Examples of legal values: CRETACEOUS, EARLY CRETACEOUS, LATE JURASSIC, EOCENE. See also Norwegian Offshore Directorate bulletins.	MIDDLE JURASSIC
1st level with HC, formation Name of lithostartigraphic unit, 1st level, where hydrocarbons were encountered. Shown only for released wells. Examples of legal values: BASEMENT, COOK FM, EKOFISK FM, HEIMDAL FM, SANDNES FM, SOGNEFJORD FM, TARBERT FM, BRENT GP. See also Norwegian Offshore Directorate bulletins.	BRENT GP
Kelly bushing elevation [m] Elevation of the rotary kelly bushing (RKB) above mean sea level.	25.0
Water depth [m] Depth in metres betweem mean sea level and sea floor.	138.0
Total depth (MD) [m RKB] Total measured length of wellbore from kelly bushing to total depth (driller's depth).	2460.0
Bottom hole temperature [°C] Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.	58
Oldest penetrated age Age (according to Geologic Time Scale 2004 by F. M. Gradstein, et al. (2004)) of the oldest penetrated formation. May differ from age at TD for example in deviated wellbores. Examples of legal values: CRETACEOUS, EARLY CRETACEOUS, LATE JURASSIC, EARLY PERMIAN, EARLY TRIASSIC, EOCENE.	LATE TRIASSIC
Oldest penetrated formation Name of the oldest lithostratigraphic unit penetrated by the wellbore. Shown only for released wells. In most wellbores this is formation or group at total depth. May differ from formation or group at TD for example in wellbores drilled with high deviation or through faults. Examples of legal values: AMUNDSEN FM, BALDER FM, BASEMENT, BLODØKS FM, BRYNE FM, BURTON FM, COOK FM, DRAKE FM, DRAUPNE FM, EKOFISK FM, DUNLIN GP.	LUNDE FM
Geodetic datum Reference system for coordinates. Example of legal values: ED50.	ED50
NS degrees Geographic coordinate of the wellhead, north-south degrees.	61° 10' 46.84'' N
EW degrees Geographic coordinate of the wellhead, east-west degrees.	2° 12' 43.67'' E
NS UTM [m] Universal Transverse Mercator coordinate of the wellhead, north-south.	6783217.39
EW UTM [m] Universal Transverse Mercator coordinate of the wellhead, east-west.	457626.92
UTM zone Universal Transverse Mercator zone. Examples of legal values: 31, 32, 33, 34.	31
NPDID wellbore Norwegian Offshore Directorate's unique id for the wellbore.	424

Well 34/10-1 was the first well to be drilled on the "Delta structure" (Gullfaks fault block) in the Northern North Sea. The primary objective of the well was to penetrate sandstones of Early to Middle Jurassic age and to evaluate their possible content of hydrocarbons.

Operations and results

Wildcat well 34/10-1 was spudded with the semi-submersible installation Ross Rig on 20 June 1978 and drilled to TD at 2460 m in the Late Triassic Lunde Formation. The 30" casing was set after considerable difficulty in getting through a section of boulders. A severe well kick was taken after a flow check at 1780 m, ca 3 m above top reservoir. Ca 440 barrels of mud were gained in the pit. Otherwise the operations proceeded without significant problems. No directional survey was run below1737 m. The well was drilled with seawater and gel slugs down to 214 m, with fresh water and gel from 214 m to 504 m, with seawater/gel/lignosulphonate from 504 m to 1970 m and with Seawater/gel/spersene/XP20 from 1970 m to TD.

First oil show, pale yellow fluorescence in limestone and siltstone, was recorded at 1370 m in the Hordaland Group. Similar shows continued down to top Brent Group level interrupted only by a short interval of no shows from 1579 to 1600 m. At 1555 in the Balder Formation trace oil in the mud was observed. Top reservoir, Tarbert Formation, was encountered at 1783 m directly underlying the Late Cretaceous Shetland Group. Oil was proven in sandstones all through the Middle Jurassic Brent Group down to top Drake Formation in the Dunlin Group. The oil/water contact was not observed in the well. Below reservoir level shows decreased and died out completely below 2325 m.

A total of 12 cores were recovered in the interval from 1782.0 to 1951.1 m and one core from 2232.5 to 2250.5 m. Three runs were made with the RFT and samples were taken at 1871 m (oil) and 2244 m (water, mud and mud filtrate).

The well was permanently abandoned on 8 September as an oil discovery.

Testing

Three drill stem tests were conducted in the Brent Formation.

DST 1 perforated the interval 1930 to 1935 m in the Rannoch Formation and produced 191 Sm3 oil and 20560 Sm3 gas /day through a 32/64" choke. No water was produced. The GOR was 108 Sm3/Sm3, the oil gravity was 28.9 deg API, and the gas gravity was 0.632 (air = 1).

DST 2 perforated the interval 1839 to 1844 m in the Etive Formation and produced 1049 Sm3 oil and 86930 Sm3 gas /day through a 36/64" choke. No water was produced. The GOR was 83 Sm3/Sm3, the oil gravity was 28.4 deg API, and the gas gravity was 0.61 (air = 1). The maximum bottom hole temperature recorded in the test was 71.7 deg C.

DST 3 perforated the interval 1788 to 1792 m in the Tarbert Formation and produced 323 Sm3 oil and 29365 Sm3 gas /day through a 17/64" choke. No water was produced. The GOR was 91 Sm3/Sm3, the oil gravity was 29 deg API, and the gas gravity was 0.62 (air = 1). The maximum bottom hole temperature recorded in the test was 69 deg C.

Cuttings at the Norwegian Offshore Directorate

Cuttings at the Norwegian Offshore Directorate
Cuttings available for sampling?	NO

Cuttings at the Norwegian Offshore Directorate
Cutting sample, top depth [m]	Cutting samples, bottom depth [m]
210.00	2460.00

Cores at the Norwegian Offshore Directorate

Cores at the Norwegian Offshore Directorate
Core sample number	Core sample - top depth	Core sample - bottom depth	Core sample depth - uom
1	1782.0	1785.9	[m ]
2	1790.5	1792.8	[m ]
3	1802.5	1815.6	[m ]
4	1819.0	1835.6	[m ]
5	1835.8	1853.3	[m ]
6	1853.3	1862.3	[m ]
7	1865.4	1873.8	[m ]
8	1875.0	1889.5	[m ]
9	1893.5	1911.3	[m ]
10	1911.3	1922.1	[m ]
11	1923.1	1938.8	[m ]
12	1938.8	1951.1	[m ]
13	2232.5	2244.5	[m ]

Cores at the Norwegian Offshore Directorate
Total core sample length [m]	153.8

Cores at the Norwegian Offshore Directorate
Cores available for sampling?	YES

Core photos

Core photos

1782-1784m	1784-1785m	1790-1792m	1802-1805m	1805-1806m

1807-1810m	1810-1813m	1813-1815m	1819-1821m	1821-1824m

1824-1827m	1827-1829m	1829-1832m	1832-1835m	1835-1835m

1835-1838m	1838-1841m	1841-1843mj	1843-1846m	1846-1849m

1849-1852m	1852-1853m	1853-1855m	1855-1858m	1858-1861m

1861-1862m	1865-1868m	1868-1870m	1870-1873m	1873-1874m

1875-1877m	1877-1880m	1880-1883m	1883-1885m	1885-1888m

1888-1889m	1893-1896m	1896-1898m	1898-1901m	1901-1904m

1904-1907m	1907-1909m	1909-1911m	1911-1914m	1914-1916m

1916-1919m	1919-1922m	1923-1925m	1925-1928m	1928-1931m

1931-1933m	1933-1936m	1936-1938m	1938-1941m	1941-1944m

1944-1946m	1946-1949m	1949-1951m	2232-2235m	2235-2237m

2237-2240m	2240-2243m	2243-2244m

Palynological slides at the Norwegian Offshore Directorate

Palynological slides at the Norwegian Offshore Directorate
Sample depth	Depth unit	Sample type	Laboratory
1782.3	[m]	C	LAP
1791.5	[m]	C	LAP
1807.0	[m]	C	LAP
1809.2	[m]	C	LAP
1811.2	[m]	C	LAP
1812.7	[m]	C	LAP
1819.0	[m]	C	LAP
1819.9	[m]	C	LAP
1824.6	[m]	C	LAP
1826.0	[m]	C	LAP
1829.3	[m]	C	LAP
1830.3	[m]	C	LAP
1832.3	[m]	C	LAP
1833.5	[m]	C	LAP
1835.6	[m]	C	LAP
1937.7	[m]	C	LAP
1940.0	[m]	C	LAP
1941.3	[m]	C	LAP
1943.7	[m]	C	LAP
1944.5	[m]	C	LAP
1945.2	[m]	C	LAP
1946.8	[m]	C	LAP
1947.1	[m]	C	LAP
1949.0	[m]	C	LAP
2238.4	[m]	C	LAP

Oil samples at the Norwegian Offshore Directorate

Oil samples at the Norwegian Offshore Directorate
Test type	Bottle number	Top depth MD [m]	Bottom depth MD [m]	Fluid type	Test time	Samples available
DST	DST1	1930.00	1935.00		21.08.1978 - 00:00	YES
DST	DST3	1788.00	1792.00		29.08.1978 - 00:00	YES

Lithostratigraphy

Lithostratigraphy
Top depth [mMD RKB]	Lithostrat. unit
163	NORDLAND GP
936	UTSIRA FM
946	HORDALAND GP
1513	ROGALAND GP
1513	BALDER FM
1582	LISTA FM
1678	SHETLAND GP
1678	JORSALFARE FM
1718	KYRRE FM
1783	BRENT GP
1783	TARBERT FM
1797	NESS FM
1833	ETIVE FM
1871	RANNOCH FM
1935	BROOM FM
1946	DUNLIN GP
1946	DRAKE FM
2023	COOK FM
2081	BURTON FM
2120	AMUNDSEN FM
2268	STATFJORD GP
2268	NANSEN FM
2329	RAUDE FM
2367	HEGRE GP
2367	LUNDE FM

Geochemical information

Geochemical information
Document name	Document format	Document size [MB]
424_GCH_1	pdf	0.66
424_GCH_2	pdf	3.66
424_GCH_3	pdf	1.04

Documents – older Norwegian Offshore Directorate WDSS reports and other related documents

Documents – older Norwegian Offshore Directorate WDSS reports and other related documents
Document name	Document format	Document size [MB]
424_01_WDSS_General_Information	pdf	0.22
424_03_WDSS_lithlog	pdf	0.06

Documents – reported by the production licence (period for duty of secrecy expired)

Documents – reported by the production licence (period for duty of secrecy expired)
Document name	Document format	Document size [MB]
424_34_10_1_ A_palynostratigraphic_study_of_11 samples	pdf	0.84
424_34_10_1_ADT_report	pdf	7.17
424_34_10_1_Analysis_of_oil	pdf	0.89
424_34_10_1_Biostratigraphy	pdf	3.53
424_34_10_1_Biostratigraphy_of_interval_210m-2462m	pdf	7.30
424_34_10_1_Brent_formation_relief_program	pdf	1.88
424_34_10_1_Capilary_pressure_measurment	pdf	7.38
424_34_10_1_CompletionReport	pdf	23.14
424_34_10_1_Completion_report	PDF	29.02
424_34_10_1_Core_description	pdf	1.72
424_34_10_1_Core_photoes_core_1-13	pdf	201.96
424_34_10_1_Data_summary	pdf	39.05
424_34_10_1_Dipmeter_analysis	pdf	2.78
424_34_10_1_Final_report_core_1-13	pdf	3.29
424_34_10_1_Geological_prognosis_&_drilling_program_consideratio	pdf	4.27
424_34_10_1_Pressure_prediction	pdf	37.61
424_34_10_1_Reservoir_fluid_analysis_DST-3_flow-3	pdf	1.27
424_34_10_1_Reservoir_fluid_study_bottom_hole_sample	pdf	1.18
424_34_10_1_Reservoir_fluid_study_DST-2 flow-2	pdf	1.24
424_34_10_1_Source_rock_crude_oil_correlation	pdf	5.67
424_34_10_1_Source_rock_evaluation (2)	pdf	4.92
424_34_10_1_Source_rock_evaluation	pdf	0.44
424_34_10_1_Special_core_analysis	pdf	18.18
424_34_10_1_Special_core_analysis_II	pdf	6.14
424_34_10_1_Special_core_analysis_study	pdf	6.46
424_34_10_1_Supplementary_report_DST_2_flow_3	pdf	0.76
424_34_10_1_Testrapport	pdf	2.12
424_34_10_1_True_boiling_point_distillation	pdf	2.35

Drill stem tests (DST)

Drill stem tests (DST)
Test number	From depth MD [m]	To depth MD [m]	Choke size [mm]
1.0	1930	1935	12.7
2.0	1839	1844	14.3
2.1	1839	1844	6.7
3.0	1788	1792	6.7

Drill stem tests (DST)
Test number	Bottom hole pressure [MPa]	Downhole temperature [°C]
1.0	13.500
2.0	29.000	72
2.1	30.000	69
3.0	30.000	69

Drill stem tests (DST)
Test number	Oil [Sm3/day]	Gas [Sm3/day]	Oil density [g/cm3]	Gas grav. rel.air	GOR [m3/m3]
1.0	191	20560	0.881	0.632	108
2.0	1048	86930	0.885	0.610	83
2.1	323	29365	0.879	0.626
3.0	322	28151	0.882	0.620

Logs

Logs
Log type	Log top depth [m]	Log bottom depth [m]
CBL GR	1400	1771
CBL VDL GR CCL	1725	1950
CBL VDL GR CCL	1760	1925
DLL MSFL GR	1725	1969
FDC CNL GR CAL	1439	2460
FDC GR CAL	487	1454
GEODIP	1776	1970
HDT	1763	1970
HDT	1969	2460
ISF SON GR SP	213	2460
LSS GR	487	1454
LSS GR	1751	1965
MECH PROP LOG	1764	1960
MECH PROP LOG	1765	1960
MLL MC CAL	1969	2460
NGS	1765	2457
TDT	80	1735
VELOCITY	0	0

Casing and leak–off tests

Casing and leak–off tests
Casing type	Casing diam. [inch]	Casing depth [m]	Hole diam. [inch]	Hole depth [m]	Formation test type
CONDUCTOR	30	213.0	36	214.0	LOT
SURF.COND.	20	488.0	26	504.0	LOT
INTERM.	13 3/8	1441.0	17 1/2	1456.0	LOT
INTERM.	9 5/8	1765.0	12 1/4	1780.0	LOT
LINER	7	1969.0	8 1/2	1970.0	LOT
OPEN HOLE		2462.0	6	2462.0	LOT

Drilling mud

Drilling mud
Depth MD [m]	Mud weight [g/cm3]	Visc. [mPa.s]	Mud type
214	1.05		waterbased
504	1.10		waterbased
1288	1.19		waterbased
1456	1.24		waterbased
1554	1.49		waterbased
1853	1.82	42.0	waterbased
2158	1.76	43.0	waterbased
2440	1.70	49.0	waterbased
2462	1.83	52.0	waterbased

Pressure plots

Pressure plots
The pore pressure data is sourced from well logs if no other source is specified. In some wells where pore pressure logs do not exist, information from Drill stem tests and kicks have been used. The data has been reported to the NPD, and further processed and quality controlled by IHS Markit.

Pressure plots
Document name	Document format	Document size [MB]
424_Formation_pressure_(Formasjonstrykk)	pdf	0.21

34/10-1